Vibrating tool

ABSTRACT

A vibrating tool comprising a hammer and valve that oscillate axially inside a housing to produce vibrations solely in response to fluid flow through the tool at an operating flow rate. The valve is supported by a spring that resists compression until a minimum operating flow rate is achieved, and hammer is also spring-loaded. When the valve strokes down and engages the hammer, flow through the hammer is restricted. Increased fluid pressure pushes the hammer down away from the valve, resulting in a sudden decrease in pressure, allowing both the hammer and valve to rebound and create vibrational impacts. The cycle repeats continuously as long as an adequate flow rate is maintained.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of provisional application Ser. No.61/174,804, filed May 1, 2009, entitled “Vibrating Tool,” the contentsof which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to downhole tools and, moreparticularly but without limitation, to vibrating tools for reducingfriction drag in coiled tubing applications.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exploded, side elevational view of a bottom holeassembly comprising a vibrating tool in accordance with the presentinvention.

FIG. 2 is a longitudinal sectional view of a vibrating tool made inaccordance with a first embodiment of the present invention.

FIGS. 3 and 4 are enlarged, sequential sectional views of the tool shownin FIG. 2.

FIG. 5 is an enlarged sectional view showing the valve of the tool shownin FIG. 2.

FIG. 6 is an enlarged sectional view showing the hammer of the toolshown in FIG. 2.

FIG. 7 is a longitudinal section view of a vibrating tool made inaccordance with a second embodiment of the present invention.

FIG. 8 is an uphole end view of the hammer member of the embodiment ofFIG. 7.

FIG. 9 is an enlarged sectional view of the hammer member of the toolshown in FIG. 7.

FIG. 10 is an enlarged sectional view of the valve and hammer sectionsof the tool shown in FIG. 7.

FIG. 11 is a further enlarged sectional view showing the valve member ofthe tool shown in FIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Coiled tubing offers many advantages in modern drilling and completionoperations. However, in deep wells, and especially in extended reachnon-vertical wells, the frictional forces between the tubing string andthe borehole wall while running the coiled tubing sometimes causebuckling and even lockup of the tubing string.

Vibrating tools have been developed for use in coiled tubing conveyedassemblies to reduce the frictional drag of the tool string. Thesevibrating tools facilitate operations in directional drillingapplications and significantly increase the depth that can be achievedduring the conveyance of the bottom hole assembly (“BHA”).

The present invention provides a friction-reduction tool that offersmany advantages. The vibrating mechanism is driven solely by controllingfluid flow through the tool; neither axial movement of the tubing stringnor the downward pressure of the tubing on the housing is required. Thestructure of the tool is simple and sturdy, providing a reliable toolthat is economical to build and maintain and easy to redress. The bodyof the tool has a relatively shorter overall length so it is easier tonegotiate through tight curves in the well bore. The vibrating mechanismis completely enclosed in a solid housing, so there are no externalparts to fall into the tools below. The tool may include a bypass areafor a logging conductor wire and is compatible with e-coil operations.The vibrations generated in the tool are sufficient to reduce frictionbetween the BHA and the wellbore but of low enough intensity to avoiddamage to other tools in the BHA. The friction-reduction tool of thepresent invention can be employed in applications such as plug-drilling,junk milling, new-well bore drilling, fishing, logging, perforating,including abrasive perforating, and any other operation in a conveyedsituation where coiled tubing or a workstring is used to transport thetools into a lateral well bore.

Turning now to the drawings in general and to FIG. 1 in particular,there is shown therein a bottom hole assembly or “BHA” comprising avibrating tool in accordance with the present invention. The vibratingtool, designated generally at 10, is shown installed in the BHA,designated generally at 12. The BHA 12 may comprise a wide assortment oftools. By way of example only, the BHA 10 shown in FIG. 1 comprises amotor head assembly 14, a downhole motor 16, and flat bottom junk mill18. The vibrating tool 10 is shown in the BHA 12 between the motor headassembly 14 and the motor 16. However, it will be appreciated that thenumber and type of tools, and the relative position of the vibratingtool 10 within the BHA, may be varied according to the specific wellconditions.

Turning now to FIGS. 2-6, a first embodiment of the vibrating tool ofthe present invention will be described. As illustrated in FIG. 2, thetool 10 comprises a solid, enclosed housing 20, that is, there are noexternal moving parts. The structure of the housing 20 may vary, but inthe preferred embodiment, the housing comprises a top sub 22, a housingbody 24, and a bottom sub 26, which are threadedly connected. The upholeend 28 of the top sub 22 may be provided with a box joint 30, and thedownhole end 32 of the bottom sub 26 may be provided with a typical pinend 34 for interconnection with the other tools in the BHA 12. Seals,such as O-rings, are used at these joints and elsewhere in the tool, andare all designated by the reference number 36. The housing 20 defines aflow path, identified by the arrow 40, extending completely through thetool 10 so that fluid flowing through the coiled tubing (not shown) canpass through the tool into the tools below it in the BHA 12.

Referring still to FIG. 2 and now also to FIGS. 3 and 4, the tool 10comprises a vibrating assembly 42 that includes a hammer 44 and a valve46. The hammer 44 and valve 46 are contained within a generally tubularvibrator housing 50, which may comprises a top sub 52, a barrel 54, anda bottom sub 56. The top sub 52 is connected to the downhole end 58 ofthe housing top sub 22, so that impacts delivered to the vibratorhousing 50 will be transmitted to the housing 20.

The hammer 44 is supported inside the vibrator housing 50 in the flowpath 40 of the tool 10 to stroke axially. In this embodiment, thevibrating assembly 42 incorporates part of the hammer mechanism shownand described in U.S. Pat. No. 6,315,063 entitled “Reciprocating RotaryDrilling Motor issued on Nov. 13, 2001 to Leo a. Martini. This patent isincorporated herein by reference.

In the Martini patent, the hammer delivers repetitive impacts to a drillbit at the end of a drill string. In the tool 10 of the presentinvention, the hammer 44 “floats” inside the vibrator housing 50. Morespecifically, the hammer 44 is resiliently supported on a spring, suchas the compression spring 60. Although a helical compression spring isshown, the term “spring” as used herein broadly denotes any form ofresilient support. For example, the spring alternately may be Bellevillewasher springs, rubber elastomer blocks, or some form of compressed airor liquid.

A stack of shims (not shown) may be used below the spring 60 to allowfine-tuning of the resistance offered by the spring 60. Additionally, asseen in FIG. 4, a filter plate 62 (FIG. 4) may be placed at the bottomof the spring 60 to capture any debris that may pass through the tool10.

Referring now also to FIGS. 5 and 6, the hammer 44 generally comprises abottom member 64, fixed to the downhole end 66 of a tubular body ormandrel 68, and a top member 70 fixed to the uphole end 72 of themandrel. The hammer 44 defines a flow path 74 through its length that iscontinuous with the flow path 40.

As best seen in FIG. 6, the bottom member 64 of the hammer 44 has animpact transmitting surface, which may take the form of an annularshoulder 76 on the uphole end 78 of the bottom member 64. The impacttransmitting surface 76 is configured to engage and thereby cause apercussive impact on an impact receiving surface on the housing 20 ofthe tool 12. The impact receiving surface may be the downhole end face82 of the bottom sub 56 of the vibrator housing 50.

The hammer 44 is supported in the flow path 40 of the tool 10 to strokeaxially and to provide in its stroke cycle an impact to the housing 20of the tool. To that end, the top member 70 and mandrel 68 are slidablysupported inside the vibrator housing 50, so that the top member acts asa piston inside a hydraulic chamber 80 formed by the vibrator housing50. Now it will be apparent that as the hammer 44 moves up and down inthe vibrator housing 50, the impact transmitting surface 76 on thebottom member 64 will repetitively and percussively impact the impactreceiving surface 82 on the bottom sub 56 of the vibrator housing 50,and these impacts will be transmitted to the tool housing 20 to causevibrations in the tool 10.

Axial movement of the hammer 44 is driven by fluid flowing through theflow paths 40 and 74 and the chamber 80 and is controlled by the valve46. Again, the valve 46 in this embodiment is substantially thatdisclosed in the above-identified Martini patent, so its structure andoperation will only be summarized.

As shown in FIG. 5, the valve 46 comprises a valve stem 90 slidablymounted in the valve support 92 non-movably fixed to the inside of thevibrator housing 50. Fluid ports 94 in the valve support 92 allow fluidto pass through the support. The downhole end of the valve head 96defines a valve contact face 97 that is engagable with a valve seat 98formed in the uphole end of the top member 70 of the hammer 44 thatforms a hammer contact face 99.

When the valve stem 90 is on the upstroke, the valve 46 is “open” withthe valve head 96 separated from the seat 98 allowing unrestricted flowof fluid through the valve support 92 and into the flow path 74 of thehammer 44. When the valve 46 is in the downstroke, with the valve head96 seated in the seat 98, fluid flow is restricted, allowing a fluidpressure differential to build in the chamber 80 above the support 92.In this embodiment, closure of the valve and hammer results in a totalblockage or occlusion of flow through the flow path in the hammer 44.However, as used herein in relation to the fluid flow, “restricted”includes reduced flow as well as complete occlusion of flow.

The valve stem 90 is biased or “uploaded” in the open or upstroke by avalve return spring, such as a helical compression spring 100, which isselected to resist downward movement of the stem until a selectedoperating flow rate is achieved. A second valve lift-off spring 102 maybe included. As indicated previously in relation to the compressionspring 60, other types of springs may be employed.

Now it will be understood that as the flow rate of fluid through thetool 10 is increased, the pressure of the fluid flow eventually willovercome the resistance of the return spring 100 and the valve stem 90will shift downwardly until the head 96 nests in the seat 98, occludingfluid flow therethrough. This is referred to herein as the “operatingflow rate.” An orifice 104 may be mounted in the flow path above thevalve stem 90 to prevent the fluid stream from directly impacting theupper end of the valve stem.

Closing of the valve results in a sudden increase in fluid pressure inthe chamber 80 above the valve support 92, which continues to move thevalve stem 90, and the hammer 44 driven by it, down until the valve stemreaches the end of its stroke distance. This occurs when the lift-offspring 102 is completely compressed forming a stop to limit the strokedistance of the valve 44.

At this point, continued pressure through the ports 94 continues to movethe top member 70 of the hammer 44, separating the valve head 96 fromthe seat 98 and reestablishing unrestricted flow through the flow path74. This sudden decrease in fluid pressure allows the valve stem 90 toreturn to its neutral position and also permits the hammer 44 torebound. As the hammer rebounds, the impact transmitting surface 76 onthe bottom member 64 of the hammer 44 hits the impact receiving surface82 on the bottom the bottom sub 56 of the vibrator housing 50, causingthe vibratory impact. As long as the minimum operating flow rate ismaintained, the cycle will repeats itself, creating vibrations in thetool.

Referring still to FIGS. 3-6, yet another feature of the vibrating toolwill be described. A secondary fluid path 108 through the tool 10 may beprovided by making the outer diameter of the vibrator housing 50slightly smaller than the inner diameter of the tool housing 20 tocreate an annulus 110. Ports 112 (FIG. 3) in a reduced diameter portion114 of the top sub 22 allow fluid to enter the annulus 110, andsimilarly ports 116 (FIG. 4) in the bottom member 64 of the hammer 44allow fluid to exit the annulus and reenter the flow path 40. Thissecondary flow path allows the use of logging conductor wire for e-coilapplications.

Directing attention now to FIGS. 7-11, a second embodiment of theinventive vibrating too will described. This embodiment, designatedherein by the reference number 10A, may be used in the BHA 12 of FIG. 1in place of the tool 10.

Like the tool 10, the tool 10A comprising a solid housing 200 that iscompletely enclosed, that is, has no external moving parts. The housing200 comprises a top sub 202, a housing body 204, and a bottom sub 206.These members are threadedly connected with O-rings 208 to provide afluid tight flow path 210 therethrough.

The vibrator assembly 218 comprises a hammer 220 resiliently supportedon a spring 222 with a flow path 224 continuous with the flow path 210in the housing 200. The bottom sub 206 includes a spring receivingportion 228 (FIG. 10) that supports the spring 222. A filter plate 230and/or shims (not shown) may be included at the base of the spring 222.

A piston-type valve 234 is supported in the housing 200 above the hammer220. A valve spring 236 is captured between an annular shoulder 238formed on the inside of the housing body 204 and a shoulder 240 formedon the outside of the valve 234, as best seen in FIG. 11. A flow path242 extends through the valve 234 and is continuous with the flow path210 through the housing 200 and the flow path 224 in the hammer 220.

The valve 234 is slidably received in a narrow diameter portion 244 ofthe housing body 204. Thus the valve 234 is configured to strokeaxially. The upstroke ends when the uphole end 246 of the valve 234meets the downhole end 248 of the top sub 202. A second annular shoulder250 on the outside of the valve 234 acts as a stop when it meets theshoulder 238 (FIG. 11) to limit the travel of the valve.

As it strokes, the valve 234 acts on the hammer 220 to control fluidflow. To that end, the uphole end 252 of the hammer 220 defines a hammercontact face 254, and the downhole end of the valve 234 defines a valvecontact face 256. In the neutral position, illustrated in FIG. 11, thehammer and valve contact faces 254 and 256 oppose each other but arespaced a distance apart forming a gap 258. The hammer 220 is providedwith flow control ports 260 in its uphole end 252 that opens on thehammer contact face 254 and communicates with the flow passage 224through the hammer 220.

Now it will be appreciated that, when the valve 234 strokes down, thevalve contact face 256 will engage the hammer contact face 254. The flowcontrol ports 260 are sized and positioned so that this contact closesoff flow through the ports, restricting fluid flow and resulting in asudden rise in the fluid pressure inside the valve 234. Preferably, thehammer contact face 254 is configured so some of its surface arearemains exposed when the valve 234 closes the ports 260, as this allowsthe fluid pressure inside the valve to act directly upon the hammer 220as well as on the valve 234.

In this way, the sudden increase in pressure will push the hammer 220further down away from the valve 234, reopening the ports 260.

When unrestricted flow through the ports 260 is reestablished, there isa sudden decrease in pressure. This permits the valve 234 and the hammer220 to rebound on their respective compression springs 236 and 222.Because the resistance of the hammer spring 22 is greater than theresistance of the valve spring 236, the hammer contact face 254 impactsthe valve contact face 256, creating a vibratory impact. Thus the hammercontact face 254 serves as impact transmitting surface and the valvecontact face 256 serves as an impact receiving surface.

As indicated, the hammer 220 strokes axially in the housing 204 as it isacted upon by the stroking valve 234 and the fluid pressure in flow path210. The length of the downstroke of the hammer 220 is determined byforce of the fluid and resistance of the spring 222. In its uppermostposition, the annular shoulder 266 formed on the outer perimeter of thehammer of the hammer 220 abuts the annular complimentary shoulder 268formed on the inside of the housing 204, as best seen in FIGS. 10 and11. However, while the tool is vibrating, the hammer 220 may not reboundfar enough to cause the hammer shoulder 266 to impact the housingshoulder 268. While in some instances this interface may serve as apoint of vibratory impact, the “chattering” of the tool more preferablyis caused by the impact of the hammer contact face 254 against the valvecontact face 256 in the rebound phase of the cycle.

Now it will be apparent that the vibrator assembly 218 of the embodiment10A, like the tool 10, is operated entirely by regulating fluid flowthrough the tool. Both the hammer and valve oscillate axially inside theclosed housing in response to fluid flow at an operating flow rate tocreate gentle but effective vibrations downhole to facilitateadvancement of the BHA. The rapidity of the vibrations can be controlledby regulating the flow rate.

As used herein, phrases such as forwards, backwards, above, below,higher, lower, uphole and downhole refer to the direction of advancementof the pipe string.

The embodiments shown and described above are exemplary. Many detailsare often found in the art and, therefore, many such details are neithershown nor described. It is not claimed that all of the details, parts,elements, or steps described and shown were invented herein. Even thoughnumerous characteristics and advantages of the present inventions havebeen described in the drawings and accompanying text, the description isillustrative only. Changes may be made in the details, especially inmatters of shape, size, and arrangement of the parts within theprinciples of the inventions to the full extent indicated by the broadmeaning of the terms. The description and drawings of the specificembodiments herein do not point out what an infringement of this patentwould be, but rather provide an example of how to use and make theinvention.

1. A vibrating tool for use in a bottom hole assembly, wherein the toolcomprises a housing defining a flow path through the tool, and the toolfurther comprising a hammer and a valve both resiliently supportedinside a solid housing for oscillating axial motions solely in responseto fluid flow through the tool at an operating flow rate.
 2. Thevibrating tool of claim 1 wherein the tool further comprises a vibratorhousing forming a fluid chamber inside the tool, wherein the hammercomprises a piston like member axially movable inside the fluid chamber,wherein the hammer has a flow path therethrough, wherein the valvecomprise a valve stem axially movable in the fluid chamber to open andclose the flow path through the piston like member of the hammer.
 3. Thevibrating tool of claim 2 wherein the housing has an impact receivingsurface, wherein the hammer further comprises a bottom member having animpact transmitting surface configured to repeatedly impact the impactreceiving surface as the hammer oscillates.
 4. The vibrating tool ofclaim 3 further defined as having an uphole end and a downhole end,herein the vibrator housing and the tool housing are configured to forman annulus therebetween defining a secondary flow path through the tool,wherein the uphole end has an inlet to provide communication from theflow path into the annulus, wherein the downhole end has an outlet toproviding communication from the annulus into the flow path.
 5. Thevibrating tool of claim 1 wherein the resilient support for the hammeris a helical compression spring.
 6. The vibrating tool of claim 5wherein the resilient support for the valve is a helical compressionspring.
 7. The vibrating tool of claim 6 wherein the resistant of thehammer spring is greater than the resistance of the valve spring.
 8. Thevibrating tool of claim 1 wherein the resilient support for the valve isa helical compression spring.
 9. The vibrating tool of claim 1 whereinthe tool housing defines a fluid chamber continuous with the flow path,wherein the valve comprises a first tubular piston movable axially inthe fluid chamber and having a valve contact face, wherein the hammercomprises a second tubular piston movable axially in the fluid chamberand having a hammer contact face, wherein the hammer further comprises aflow path extending through the hammer, and wherein the valve contactface and the hammer contact face are configured so that when the valvecontact face engages the hammer contact face fluid flow through the flowpath in the hammer is restricted and so that when the hammer contactface is spaced a distance from the valve contact face fluid flow throughthe flow path in the hammer is unrestricted.
 10. A vibrating toolcomprising: a tool housing defining a fluid-tight flow path; a hammersupported in the flow path of the tool to stroke axially therein inresponse to fluid flow through the tool and having a hammer contactface, wherein the hammer defines a hammer flow path extending from thecontact face and continuous with the flow path of the tool housing; avalve supported in the flow path of the tool to stroke axially thereinin response to fluid flow through the tool and having a valve contactface, wherein the valve defines a valve flow path extending from thevalve contact face and continuous with the flow path of the tool housingand the hammer flow path; a valve return spring configured to resistdownward movement of the valve until at least an operating flow ratethrough the flow path of the tool is achieved; a hammer springconfigured to resist downward movement of the hammer, the hammer springhaving a greater resistance than the valve spring; wherein the valve ispositioned in the housing above the hammer so that when the tool is inthe neutral position the valve contact face opposes and is spaced adistance from the hammer contact face permitting unrestricted flow fromthe valve flow path to the hammer flow path and so that in response toan operating flow rate the valve strokes downward against the resistanceof the valve spring to bring the valve contact face into engagement withthe hammer contact face; and wherein the hammer and valve are configuredfor performing a repetitive vibratory cycle in which, when the hammerand valve contact faces engage, flow through the hammer flow path isrestricted to produce increased fluid pressure on the hammer contactface to stroke the hammer down against the resistance of the hammerspring, which in turn separates the contact faces causing a pressuredecrease, which then allows the hammer and the valve to rebound causingan impact within the housing to vibrate the tool, the cycle repeatingfor so long as the operating flow rate is maintained.
 11. The vibratingtool of claim 10 further comprising a stop for limiting the downwardaxial movement of the valve.
 12. The vibrating tool of claim 11 whereinthe valve comprises a valve stem axially supported in a valve support,wherein the tool further comprises a second valve lift-off spring, andwherein the downward travel of the valve is limited by the valvelift-off spring.
 13. The vibrating tool of claim 11 wherein the toolhousing defines an annular shoulder surrounding the valve, wherein thevalve comprises a tubular piston having an outer diameter that definesan annular shoulder configured to engage the annular shoulder on thehousing to limit the downward travel of the valve.